Cyclonic surface cleaning apparatus with a filtration chamber external to the cyclone

ABSTRACT

A surface cleaning apparatus comprises a filtration apparatus comprising a cyclone downstream from the dirty air inlet and an openable filtration chamber comprising a screen downstream from the cyclone and upstream from the suction motor. The filtration chamber is accordingly a separate volume to that of the cyclone chamber and accordingly may be accessed to clean the screen independently of opening the cyclone chamber.

FIELD

This application relates to surface cleaning apparatus, such as vacuumcleaners.

BACKGROUND

The use of a cyclone, or multiple cyclones connected in parallel orseries, is known to be advantageous in the separation of particulatematter from a fluid stream. Currently, many vacuum cleaners, which aresold for residential applications, utilize at least one cyclone as partof the air filtration mechanism.

U.S. Pat. No. 4,826,515 (Dyson) discloses a cyclonic vacuum cleanerhaving two cyclonic stages, namely a first stage for separating largerparticulate matter from an air stream and a second stage for separatingfiner particulate matter from the same air stream. Each cyclonic stagecomprised a single cyclone wherein separated particulate matter wascollected in the bottom of the cyclones. Vacuum cleaners, which use acyclonic cleaning stage comprising a plurality of cyclones in parallel,are also known.

As the cyclonic stage or stages fill, a user should empty the cyclonicstage or stages. Accordingly, the cyclonic stage or stages, or theentire vacuum cleaner, may be transported to a position above areceptacle (e.g. a garbage bin or a drain) and opened so as to allow thedirt or fluid to pour into the receptacle.

In order to inhibit hair and other larger matter from travelingdownstream from a cyclone, a shroud, screen or filter is typicallyplaced in covering relationship to the cyclone air outlet. From time totime, the shroud, screen or filter may become clogged and requirecleaning.

SUMMARY

In accordance with this invention, a surface cleaning apparatuscomprises a filtration apparatus having a cyclone. The cyclone has anair inlet and an air outlet. A screen, such as a mesh wire screen, ispositioned exterior to the cyclone in a filtration chamber, e.g.,adjacent the cyclone air outlet. Accordingly, after the air exits thecyclone, the air passes through the screen. The screen may be accessedfor cleaning by an access door, which is provided exterior to thecyclone (e.g. a door on an outer casing of the filtration apparatus).

In accordance with the prior art, a shroud or a screen may be providedinterior of a cyclone (i.e., in the cyclone chamber). During use of thesurface cleaning apparatus, elongate member such as hair and fibres maybecome adhered to the outer surface of the shroud or screen.Accordingly, in order to maintain the optimal cleaning efficiency of thevacuum cleaner, the shroud or screen must be cleaned from time to time.Either access must be provided to the interior of the cyclone to cleanthe shroud or screen, or, alternately, the shroud or screen must beremovable. In accordance with this embodiment, a screen or otherfiltration member is positioned exterior to the cyclone. Accordingly, itis not necessary to remove a screen or shroud positioned within acyclone chamber or to access the interior of the cyclone chamber inorder to clean the screen.

In a particularly preferred embodiment, a cyclone chamber has nointerior screen, shroud or filter covering the cyclone air outlet.Accordingly, no member requiring cleaning is positioned inside thecyclone chamber or surrounding the cyclone outlet (e.g. surrounding thevortex finder) and accordingly the cyclone outlet, e.g., the inlet to avortex finder, is unobstructed.

The screen may have a surface area that is 2 times, preferably at leastabout 5 times, more preferably at least about 10 times and, mostpreferably at least about 20 times, e.g. 20-50 times, the crosssectional area of the cyclone air outlet. It will be appreciated thatthe screen may be flat or may be curved, e.g., bowl shaped. The use ofsuch a large screen enhances the time during which the vacuum surfacecleaning apparatus may be used without having to clean or replace thescreen. Further, by positioning the screen exterior to the cyclonechamber, a large screen may be provided without reducing the size of thecyclone chamber.

In accordance with the invention, there is provided a surface cleaningapparatus comprising:

-   -   (a) a dirty air inlet;    -   (b) a filtration apparatus comprising a cyclone downstream from        the dirty air inlet, the cyclone having a cyclone air outlet;    -   (c) a cyclone dirt collection chamber;    -   (d) a suction motor;    -   (e) a clean air outlet downstream from the suction motor; and,    -   (f) an openable filtration chamber comprising a screen, the        filtration chamber is mounted to the surface cleaning apparatus        and positioned downstream from the cyclone air outlet and        upstream from the suction motor.

In any embodiment, the filtration chamber may be openable independentlyof the dirt collection chamber. Alternately, the cyclone and the dirtcollection chamber are openable independently of the filtration chamber.

In any embodiment, the screen may be moveably mounted, preferablyremovably mounted, in the filtration chamber, such as by being moveablymounted or removably mounted to an access door provided for thefiltration chamber.

In any embodiment, the cyclone air outlet may comprise a vortex finder,the vortex finder may have an inlet positioned inside the cyclone andthe inlet may be unobstructed.

In any embodiment, the dirt collection chamber may be positioned aroundat least a portion of the cyclone, the cyclone may have a dirtcollection area and the dirt collection chamber and the cyclone may beconcurrently openable. For example, the dirt collection chamber may havea dirt collection surface that is moveable, the cyclone may have acyclone wall that is moveable and is connected to the moveable dirtcollection surface, whereby both the cyclone wall and the dirtcollection surface may be moveable concurrently such that the dirtcollection chamber and the cyclone are concurrently emptyable.

In such an embodiment, the dirt collection surface and the cyclone wallmay comprise a pivoting wall of the filtration apparatus. Preferably,the cyclone wall includes a vortex finder mounted thereto. Preferably,the pivoting wall is a lower surface of the filtration apparatus. Thefiltration chamber may be mounted to the pivoting wall.

In any embodiment, at least a portion of the filtration chamber may betransparent. For example, the filtration chamber may have an access doorthat is at least partially transparent, and preferably all of the accessdoor is transparent.

In any embodiment, the cyclone may be inverted. However, it will beappreciated that the positioning of the screen may be used with acyclone of any configuration or orientation. Further, the positioningmay be used if a cyclonic stage comprises a single cyclone or aplurality of cyclones, or even if a plurality of cyclonic stages areused in series. If a plurality of cyclonic stages are provided, then itis preferred that the screen is positioned downstream of the firstcyclonic stage and upstream of the next cyclonic stage.

It will be appreciated that the filtration chamber may be removablymounted to the filtration apparatus. Accordingly, the filtration chambermay be removed and then emptied. For example, once the filtrationchamber is removed from the filtration apparatus, the filtration chambermay then be opened, e.g., by pivoting, sliding or translating a wall,e.g., the lower surface, of the filtration chamber. Alternately, thefiltration chamber may be opened as it is removed. For example, the topof the filtration chamber may be removably mounted to the filtrationapparatus by means of a screw mount or a bayonet mount with the matingsurface of the filtration apparatus comprising a wall, e.g., a top, ofthe filtration chamber. Thus, when the filtration chamber is removed, itis open for emptying.

Preferably, the filtration chamber is mounted to the cyclone. Forexample, it may be mounted to the cyclone casing that houses the cycloneor any of the cyclonic stages.

It will be appreciated that the cyclone may be emptied when mounted tothe surface cleaning apparatus. Accordingly, the filtration chamber maybe openable while mounted to the surface cleaning apparatus so that itmay be emptied when still affixed to the surface cleaning apparatus.Alternately, if the filtration chamber is removably mounted to thefiltration apparatus, it may be removed from the surface cleaningapparatus for emptying.

It will also be appreciated that the cyclone (e.g., the filtrationapparatus) may be removed from the surface cleaning apparatus foremptying. In such a case, the filtration chamber is preferably removablewith the filtration apparatus, i.e. mounted or removably mounted to thefiltration apparatus. It will also be appreciated that the filtrationchamber may remain on the surface cleaning apparatus when the cyclone isremoved for emptying.

It will also be appreciated that in any embodiment, additional screensand/or filtration members may be used.

In accordance with the invention, there is also provided a preferredembodiment comprising:

-   -   (a) a dirty air inlet;    -   (b) a filtration apparatus having a lower surface and comprising        a cyclone downstream from the dirty air inlet, the cyclone        having a dirt outlet and a cyclone floor;    -   (c) a dirt collection chamber in communication with the dirt        outlet and having a dirt collection chamber floor;    -   (d) an access door is provided on the lower surface, a        filtration chamber is positioned between the lower surface and        the access door and a screen is provided in the filtration        chamber adjacent the lower air outlet of the cyclone;    -   (e) a suction motor; and,    -   (f) a clean air outlet downstream from the suction motor.

In one such embodiment, the dirt collection chamber is positioned aroundat least a portion of the cyclone, the dirt collection chamber floor ismoveable, the cyclone floor is moveable and is connected to the lowermoveable dirt collection chamber floor and the lower surface comprisesthe cyclone floor and the dirt collection chamber floor, whereby boththe cyclone floor and the dirt collection chamber floor are moveableconcurrently such that the dirt collection chamber and the cyclone areconcurrently emptied.

In another such embodiment the dirt collection chamber floor and thecyclone floor comprise a pivoting bottom of the filtration apparatus.

In another such embodiment the cyclone floor includes a vortex findermounted thereto. The screen may be positioned beneath the vortex finder.

It will be appreciated by those skilled in the art that any of theembodiments may be used individually or in a single surface cleaningapparatus, as exemplified in a preferred embodiment described herein, orin any particular sub-combination. Accordingly, any two or moreembodiments may be used in a single surface cleaning apparatus. Inaddition, any of the optional features described herein may be used incombination with any alternate embodiment or sub-combination orcombination of alternate embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other advantages of the instant invention will be more fullyand completely understood in conjunction with the following descriptionof the preferred embodiments of the invention in which:

FIG. 1 is a side elevational view of a preferred embodiment of a vacuumcleaner in accordance with this design wherein the outer casingsurrounding the cyclone and forming an outer wall of a dirt collectionchamber is optionally transparent;

FIG. 2 is a perspective view from the front and the right side of thevacuum cleaner of FIG. 1;

FIG. 3 is a cross-section along the line 3-3 in FIG. 2;

FIG. 4 is a schematic drawing of the vacuum cleaner of FIG. 1 showingthe airflow passage therethrough;

FIG. 5 is a perspective view from the bottom of the vacuum cleaner ofFIG. 1 wherein the bottom of the first and second housings is open; and,

FIG. 6 is a perspective view of the bottom of the vacuum cleaner of FIG.1 wherein the first and second housings are closed but an access door isopen.

DETAILED DESCRIPTION

As shown in FIGS. 1-6, a surface cleaning apparatus comprises a vacuumcleaner 10 having a filtration apparatus having at least one cyclone.The filtration apparatus may be of any design or configuration. Asexemplified, surface cleaning apparatus 10 has a first housing 12 and asecond housing 14. First housing 12 comprises at least one cyclone 16and a dirt collection chamber 18 and second housing 14 houses thefiltration members and the suction motor. In an alternate embodiment, itwill be appreciated that surface cleaning apparatus 10 may have a firstcyclonic cleaning stage comprising a single cyclone having a dirtcollection chamber and a second cyclonic cleaning stage comprising aplurality of second stage cyclones in parallel. It will be appreciatedthat only a single filter may be provided and a side by sideconstruction need not be used.

As exemplified in FIG. 3, suction motor 26 is positioned in secondhousing 14, preferably with a suction fan provided below the electricmotor. Clean air outlet 60 is provided downstream from suction motor 26.An optional post-motor filter may be provided downstream from suctionmotor 26, such as in post-motor filter housing 62, which may beaccessible via post motor filter housing door 64, which could bepivotally mounted to second housing 14.

As exemplified in FIGS. 1-6, vacuum cleaner 10 comprises a hand heldvacuum cleaner. Accordingly, vacuum cleaner 10 may be provided withhandle 54, which is affixed to lid 32 and lid 58 of second housing 14.Handle 54 may alternately be affixed to any other portion or portions ofvacuum cleaner 10 as is known in the art. Optionally, as exemplified,on/off switch 56 may be provided on handle 54. On/off switch 56 mayalternately be provided on any other portion of vacuum cleaner 10.

It will be appreciated that, surface cleaning apparatus may be a vacuumcleaner, a carpet extractor, a bare floor cleaner or the like. Asexemplified, the surface cleaning apparatus is hand held. However thesurface cleaning apparatus may be configured as an upright vacuumcleaner, a stick vacuum cleaner, a canister vacuum cleaner, a backpackor shoulder strap vacuum cleaner or other configuration known in theart. The surface cleaning apparatus may have a single cyclonic cleaningstage, which may be of any construction known in the art, or a pluralityof cyclonic cleaning stages, each of which may be of any constructionknown in the art, e.g. they may comprise a single cyclone or a pluralityof cyclones in parallel.

The following description is based on FIGS. 1-6, which exemplifies theinvention in accordance with the use of an inverted cyclone. However, inan alternate embodiment, it will be appreciated that the cyclone 16 maybe of any configuration and orientation and need not be inverted (e.g.,cyclone 16 may be a horizontally mounted cyclone or a vertically mountedupright cyclone with an upper air inlet, an upper air out and a lowerdirt outlet). Accordingly, the reference to “upper” and “lower” and“floor” are for convenience in the following discussion and relate to apreferred embodiment.

As exemplified in FIG. 3, cyclone 16 has a lower air inlet 34 and alower air outlet 36. Air inlet 34 is positioned downstream from dirtyair inlet 38 of surface cleaning nozzle 40. Surface cleaning nozzle 40may be any surface cleaning nozzle known in the art. Air inlet 34 ofcyclone 16 may be in airflow communication with surface cleaning nozzle40 in any manner known in the art. The exact structure of surfacecleaning nozzle 40 and the communication passage between surfacecleaning nozzle 40 and air inlet 34 will vary depending if the surfacecleaning apparatus is an upright vacuum cleaner, canister vacuum cleaneror, as exemplified, a portable hand held vacuum cleaner. In operation,air will enter cyclone 16 through inlet 34 and travel upwardly, asexemplified in FIG. 4. The air will then travel downwardly to exitcyclone 16 via outlet 34. As shown in FIG. 4 by the hatched arrows, dirtwill exit upwardly through outlet 28 and deposit on dirt collectionchamber floor 42. In addition, some of the heavier particulate mattermay not be entrained in the air stream and may be deposited on cyclonefloor 34.

In an alternate embodiment, it will be appreciated that cyclone 16 maybe any cyclone casing having a separator plate to divide the cyclonecasing into an upper cyclone chamber positioned above the separatorplate and a lower dirt collection chamber positioned below the separatorplate. Alternately, the cyclone may be provided with a dirt outlet 28and may be provided with an impingement member 30 or members spaced adistance D from the dirt outlet and facing the dirt outlet. The cyclonemay be an upright cyclone or a cyclone having a single direction oftravel of the air.

As exemplified, cyclone 16 is a frustoconical cyclone having cylindricalportion 46 and frustoconical portion 48. Alternately, or in addition tothe orientation of cyclone 16, it will be appreciated that cyclone 16may be cylindrical, entirely frustoconical or any other shape known inthe art.

As exemplified in FIG. 3, outlet 36 of cyclone 16 comprises a vortexfinder that extends inwardly into the cyclone chamber defined by cyclone16. Outlet 36 preferably comprises a generally cylindrical passagehaving an inlet 50 and an outlet 52. It will be appreciated that, in analternate embodiment any outlet or vortex finder known in the art forcyclones may be utilized. While inlet 50 may be covered by a screen,shroud or filter as in known in the art, it is preferred that no screen,shroud or filter is provided. Accordingly, inlet 50 will not becomeclogged during use and will not require cleaning. Accordingly, it willbe appreciated that bottom 44 need not be openable to permit a screen ora shroud or filter associated with inlet end 50 of outlet 36 to becleaned. The material that would otherwise clog a screen or shroud thatsurrounds inlet 50 will be retained by screen 78 which may be easilyaccessed and with may be larger than a screen in a cyclone chamber.

While the use of impingement member 30 is exemplified in a surfacecleaning apparatus having side-by-side housings 12, 14, it will beappreciated that this design may be used in any vacuum cleanerconfiguration. It will also be appreciated that an impingement surfaceneed not be used.

In accordance with any embodiment of this invention, dirt collectionchamber 18 may surround at least a portion of and, as exemplified,preferably all of cyclone 16. Accordingly, cyclone 16 may be positionedin dirt collection chamber 18 and, preferably, generally centrallytherein.

In accordance with any embodiment, vacuum cleaner 10 may be configuredsuch that the dirt collected on floor 44 of cyclone 16 is emptied at thesame time as dirt collected on floor 42 of dirt collection chamber 18.The following description refers to the embodiment of FIGS. 1-6 whereinthe openable end of the dirt collection camber is the dirt collectionsurface (floor 42). However, in an alternate embodiment, it will beappreciated that the openable portion need not be the dirt collectionsurface. For example, if cyclone 16 is mounted horizontally, then theopenable portion may be the end of dirt collection chamber 18 facingdirt outlet 28 to which impingement member 30 is attached. In such acase, the dirt collection surface will be a sidewall of dirt collectionchamber 18.

As exemplified, floor 42 and floor 44 are both movable and connected toeach other whereby both floor 42 and 44 are concurrently movable suchthat dirt collection chamber 18 and cyclone 16 are concurrently emptied.In an alternate embodiment, dirt collection chamber 18 may be providedin the bottom of cyclone 16.

Referring to FIG. 5, floors 42 and 44 may comprise a pivoting bottom offirst housing 12 and, alternately, of the filtration apparatus (e.g.housings 12 and 14 of this embodiment). Accordingly, as seen in FIG. 5,when floors 42 and 44 are opened, both cyclone 16 and dirt collectionchamber 18 may be emptied by holding vacuum cleaner 10 in the uprightposition (as shown in FIG. 1). Accordingly, the dirt will fall out ofcollection chamber 16 and cyclone 16 and will fall downwardly off offloors 42 and 44.

As shown in FIG. 5, housings 12 and 14 have a pivoting bottom 66, whichis secured to each of housings 12 and 14 by a pivot 68. In the closedposition exemplified in FIGS. 1 and 4, pivoting bottom 66 is secured inposition by latch 70. Latch 70 has a button 72 which, when pressed,causes arm 74 to move outwardly thereby disengaging a flange provided onthe bottom end of arm 74 from flange 76 provided on pivoting bottom 66.A gasket or other sealing member may be provided at the interface ofhousings 12 and 14 and pivoting bottom 66 to provide an air tight orfluid tight seal. It will be appreciated that bottom 66 may be moveablein any other direction by any other means known in the art (e.g.,slideable, translatable) and may optionally be removable from housings12, 14 (e.g., by a snap fit, a screw mount, a bayonet mount or thelike). Further, bottom 66 may be moveably secured in position by anyother means known in the art and need not be connected to surfacecleaning apparatus 10 for relative motion thereto.

As exemplified in FIG. 5, outlet 36 is provided as part of floor 42, andis preferably integrally molded therewith. In an alternate embodiment,it will be appreciated that outlet 36 need not be removable from cyclone16 with floor 42.

In an alternate embodiment, it will be appreciated that only floors 42and 44 may be pivotably mounted to housing 12. In such an embodiment,foam filter 20 may remain sealed when cyclone 16 and dirt collectionchamber 18 are emptied. In an alternate embodiment, a side-by-side ofhousings 12, 14 design as exemplified in FIG. 1 need not be utilized. Insuch a case, floor 42 and floor 44 may comprise the entire floor of thefiltration assembly.

If bottom 66 opens both housings 12 and 14, then it will be appreciatedthat dirt positioned on the upstream surface of filter 20 will beemptied when bottom 66 is opened.

As exemplified, screen 78 is provided in an openable filtration chamber80. As exemplified, filtration chamber 80 is provided as part of thelower surface of cyclone 16. It will be appreciated that it is preferredthat filtration chamber 80 is positioned adjacent air outlet 36 ofcyclone 16, or downstream of the first cyclonic stage if a plurality ofcyclonic stages are provided. If filtration chamber is positioned besidecyclone 16, e.g., it is located where foam filter 20 is provided, itwill be appreciated that filtration chamber 80 and cyclone 16 may beconcurrently opened, e.g., by a pivoting bottom 66. Alternately, or inaddition, using a similar construction, filtration chamber 80 may beopened when dirt collection chamber 18 is opened.

As exemplified, filtration chamber 80 is openable independently of anyother member, e.g., cyclone 16, dirt collection chamber 18 and thechamber housing foam filter 20. Also, as exemplified, the lower surfaceof filtration chamber 80 is openable. However, it will be appreciatedthat an alternate wall or portion of filtration chamber 80 may beopenable and that filtration chamber 80 may be at alternate locations ona surface cleaning apparatus provided it is located downstream in thefluid flow path through the surface cleaning apparatus from the firstcyclonic cleaning stage.

As exemplified, filtration chamber 80 is provided adjacent outlet 36and, preferably, screen 78 is in sealing engagement with outlet 52. Itwill be appreciated that screen 80 is preferably mounted in filtrationchamber 80 such that the air exiting cyclone 16 is forced to passthrough screen 78 as the air travel downstream of filtration chamber 80(e.g., to a second cyclonic cleaning stage or foam filter 80). Referringto FIG. 3, screen 78 is positioned on rear surface 84 of floor 44 andoverlies outlet 52. Accordingly, air that exits outlet 36 travelsthrough screen 78. The air then travels through filtration chamber 80and travels laterally to outlet 86, which is in air flow communicationwith headspace 88 below filter 20.

Preferably, screen 78 comprises a screen, such as an open mesh screen,e.g., a wire mesh screen or, alternately, a plastic mesh screen. It maybe flat or curved, e.g. bowl shaped, so as to increase the surface areaof the screen.

In one embodiment, filtration chamber 80 has an openable portion.Accordingly, an access door 82 may be provided to permit access toscreen 78 such that screen 78 may be cleaned. Access door 82 may be anydoor that is movably mounted in overlying relationship to filtrationchamber 80. It will also be appreciated that if filtration chamber 80 isremovably mounted to surface cleaning apparatus 10, it may be opened asit is removed from surface cleaning apparatus 10. For example, a wall ofsurface cleaning apparatus 10 to which filtration chamber 80 is attachedmay close the side of filtration chamber 80 that abuts surface cleaningapparatus 10. However, it is preferred that a lower surface offiltration chamber 80 is openable.

As exemplified in FIG. 6, access door 82 may be pivotally mounted bypivot 90 to pivoting bottom 66, and is secured in position by a latch120. Latch 120, for example, may have a button 122 which, when pressed,causes arm 124 to move outwardly thereby disengaging a flange on thebottom end of arm 124 from flange 92 provided on the front end of accessdoor 82. A sealing gasket or other sealing member known in the art maybe utilized to provide an air tight or fluid tight seal for filtrationchamber 80. Any other securing member known in the art may be used.Further door 82 may be removable and need not be connected to surfacecleaning apparatus 10 for relative (e.g., sliding, translation) motionthereto.

Preferably, screen 78 is mounted and, more preferably, movably mountedand, most preferably, removably mounted to access door 82. As shown inFIG. 6, screen 78 is pivotally mounted to the inner surface of accessdoor 82. Accordingly, when a user desires to clean screen 78, it may bepivoted in the direction shown by arrow A in FIG. 6 to an open orcleaning position. Alternately, screen 78 may be movably mounted and,preferably, removably mounted to another portion of filtration chamber80.

It will be noticed that access door 82 may be opened independently ofpivoting bottom 66. In an alternate embodiment, it will be appreciatedthat a pivoting bottom 66 need not be provided.

Preferably, at least a portion of and, more preferably, all of accessdoor 82 is transparent. Accordingly, a user may lift the vacuum cleaner,invert the vacuum cleaner or tilt the vacuum cleaner on its side to viewscreen 78 and determine whether filtration 78 requires cleaning or,alternately, replacement. It will be appreciated that another part offiltration chamber 80, preferably all of filtration chamber 80, may betransparent.

As exemplified in FIG. 3, vortex finder 36 is not surrounded by a screenor any shroud or filter. In accordance with a preferred embodiment,vortex finder 36 has no cover member (e.g. shroud, screen or the like).

Accordingly, no filtration or screen member interior of cyclone 16requires cleaning. Accordingly, it will be appreciated that bottom 44need not be openable to permit a screen or a shroud or filter associatedwith inlet end 50 of outlet 36 to be cleaned.

In accordance with any embodiment of this invention, a series filtrationmembers may be used in series downstream from screen 78. In accordancewith this preferred embodiment, the filtration members may comprise twoor more of a foam filter 22 downstream from screen 78, a felt filter 22downstream from foam 20 and a HEPA filter 24 downstream from felt filter22. Preferably, all of these filters are positioned upstream fromsuction motor 26. Alternately, one or more of these filters may bepositioned downstream from suction motor 26. In particular HEPA filter24 may be downstream from suction motor 26. Accordingly, a plurality ofscreening and filtration members, each of which have a finer filtrationcapacity (e.g. smaller pores) are provided in series in the downstreamdirection. Optionally, a shroud (e.g. a perforated or apertured plasticcover) may be provided surrounding or overlying inlet 50 of outlet 36.

It will also be appreciated that any of the aforementioned embodimentsmay be used singly or in any particular combination or sub-combinationof the remaining features listed above.

Although the invention has been described in conjunction with specificembodiments thereof, if is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims. In addition, citation or identification of anyreference in this application shall not be construed as an admissionthat such reference is available as prior art to the present invention.

1. A surface cleaning apparatus comprising: (a) a dirty air inlet; (b) afiltration apparatus comprising a cyclone downstream from the dirty airinlet, the cyclone having a cyclone air outlet; (c) a cyclone dirtcollection chamber; (d) a suction motor; (e) a clean air outletdownstream from the suction motor; and, (f) an openable filtrationchamber comprising a screen, the filtration chamber is mounted to thesurface cleaning apparatus and positioned downstream from the cycloneair outlet and upstream from the suction motor.
 2. The surface cleaningapparatus of claim 1 wherein the filtration chamber is openableindependently of the dirt collection chamber.
 3. The surface cleaningapparatus of claim 1 wherein the cyclone and the dirt collection chamberare openable independently of the filtration chamber.
 4. The surfacecleaning apparatus of claim 1 wherein the screen is moveably mounted inthe filtration chamber.
 5. The surface cleaning apparatus of claim 1wherein the filtration chamber has an access door and the screen ismoveably mounted to the access door.
 6. The surface cleaning apparatusof claim 1 wherein the screen is removeably mounted in the filtrationchamber.
 7. The surface cleaning apparatus of claim 1 wherein the screenhas a surface area that is at least twice the surface area of the crosssectional area of the cyclone air outlet.
 8. The surface cleaningapparatus of claim 1 wherein the screen has a surface area that is atleast about five times the surface area of the cross sectional area ofthe cyclone air outlet.
 9. The surface cleaning apparatus of claim 1wherein the cyclone air outlet comprises a vortex finder, the vortexfinder has an inlet positioned inside the cyclone and the inlet isunobstructed.
 10. The surface cleaning apparatus of claim 1 wherein thedirt collection chamber is positioned around at least a portion of thecyclone, the cyclone has a dirt collection area and the dirt collectionchamber and the cyclone are concurrently openable.
 11. The surfacecleaning apparatus of claim 10 wherein the dirt collection chamber has adirt collection surface that is moveable, the cyclone has a cyclone wallthat is moveable and is connected to the moveable dirt collectionsurface, whereby both the cyclone wall and the dirt collection surfaceare moveable concurrently such that the dirt collection chamber and thecyclone are concurrently emptyable.
 12. The surface cleaning apparatusof claim 11 wherein the dirt collection surface and the cyclone wallcomprise a pivoting wall of the filtration apparatus.
 13. The surfacecleaning apparatus of claim 12 wherein the cyclone wall includes avortex finder mounted thereto.
 14. The surface cleaning apparatus ofclaim 12 wherein the pivoting wall is a lower surface of the filtrationapparatus.
 15. The surface cleaning apparatus of claim 1 wherein atleast a portion of the filtration chamber is transparent.
 16. Thesurface cleaning apparatus of claim 1 wherein the filtration chamber hasan access door that is at least partially transparent.
 17. The surfacecleaning apparatus of claim 1 wherein the cyclone is inverted.
 18. Thesurface cleaning apparatus of claim 1 wherein the filtration chamber isremovably mounted to the filtration apparatus.
 19. The surface cleaningapparatus of claim 1 wherein the filtration chamber is mounted to thecyclone.
 20. The surface cleaning apparatus of claim 12 wherein thefiltration chamber is mounted to the pivoting wall.
 21. The surfacecleaning apparatus of claim 1 wherein the filtration chamber is mountedto the filtration apparatus.